Tone changing and tone marking apparatus for guitars

ABSTRACT

Apparatus for selectively loosening and tightening the strings of a guitar while the guitar is being played to change the tone of the strings and thereby produce different chord combinations. A series of tone changers is mounted adjacent each end of a bank of guitar strings, each tone changer engaging a respective guitar string for selectively tightening or loosening it. The tone changers are selectively actuated by pedals or knee levers, or a combination of both, through a series of tension members and rotatable axle cranks. Each pedal comprises a primary lever coupled with one or more tone changers for causing single or multiple string tension adjustments, and a secondary lever mounted on the primary lever which can be selectively actuated simultaneously with the primary lever for causing additional string tension adjustments different from those caused by actuation of the primary lever alone. Some of the pedals are mounted to rotate only about a horizontal axis, while others are universally mounted for rotation about both a horizontal and a vertical axis. Such universally mounted pedals are capable of actuation in four different modes for producing four different tone adjustment combinations. The knee lever system comprises a set of six knee levers for each knee, two of the levers being arranged horizontally with their free ends adjacent to one another, two other levers depending vertically from mounting points adjacent the journaled ends of the aforementioned pair of horizontal levers, and a third pair of horizontal levers located in a vertical plane inboard of the other four levers. The rotatable axles by which the various pedals and knee levers are coupled with their respective tone changers are mounted transversely to and beneath the bank of guitar strings, and each includes a plurality of upper and lower cranks protruding therefrom. The cranks are threaded into upper and lower rows of sockets in each axle, and can be easily removed and relocated if it is desired to alter the guitar for different tone changing combinations. Each individual tone changer is constructed of three arms pivotally connected end to end, the middle arm being engaged by a pair of tension members actuated by cranks on the rotatable axles. One of the tension members causes the tone changer to loosen its respective string and the other causes tightening of the string when pulled. The guitar also includes a tone marking panel beneath the guitar strings which is magnetically mounted to the guitar sounding board so that it may be easily detached and replaced.

United States Patent [1 Wheeler [451 Jan. 15, 1974 4] TONE CHANGING AND TONE MARKING APPARATUS FOR GUITARS Willard L. Wheeler, 2251 N. Watts, Portland, Oreg. 97217 22 Filed: June 22,1972

211 App]. No.: 265,293

[76] Inventor:

Primary ExaminerLawrence R. Franklin Attorney-Daniel P. Chernoff et al.

[57] ABSTRACT Apparatus for selectively loosening and tightening the strings of a guitar while the guitar is being played to change the tone of the strings and thereby produce different chord combinations. A series of tone changers is mounted adjacent each end of a bank of guitar strings, each tone changer engaging a respective guitar string for selectively tightening or loosening it. The tone changers are selectively actuated by pedals or knee levers, or a combination of both, through a series of tension members and rotatable axle cranks. Each pedal comprises a primary lever coupled with one or more tone changers for causing single or multiple string tension adjustments, and a secondary lever mounted on the primary lever which can be selectively actuated simultaneously with the primary lever for causing additional string tension adjustments different from those caused by actuation of the primary lever alone. Some of the pedals are mounted to rotate only about a horizontal axis, while others are universally mounted for rotation about both a horizontal and a vertical axis. Such universally mounted pedals are capable of actuation in four different modes for producing four different tone adjustment combinations. The knee lever system comprises a set of six knee levers for each knee, two of the levers being arranged horizontally with their free ends adjacent to one another, two other levers depending vertically from mounting points adjacent the journaled ends of the aforementioned pair of horizontal levers, and a third pair of horizontal levers located in a vertical plane inboard of the other four levers. The rotatable axles by which the various pedals and knee levers are coupled with their respective tone changers are mounted transversely to and beneath the bank of guitar strings, and each includes a plurality of upper and lower cranks protruding therefrom. The cranks are threaded into upper and lower rows of sockets in each axle, and can be easily removed and relocated if it is desired to alter the guitar for different tone changing combinations. Each individual tone changer is constructed of three arms pivotally connected and to end, the middle arm being engaged by a pair of tension members actuated by cranks on the rotatable axles. One of the tension members causes the tone changer to loosen its respective string and the other causes tightening of the string when pulled. The guitar also includes a tone marking panel beneath the guitar strings which is magnetically mounted to the guitar sounding board so that it may be easily detached and replaced.

10 Claims, 6 Drawing Figures PATENTEBJAN 1 51974 $195,233

PAIENIED JAN 151974 'SHEEIZUF3 TONE CHANGING AND TONE MARKING APPARATUS FOR GUITARS BACKGROUND OF THE INVENTION This invention relates to improvements in apparatus for adjusting guitar string tension while the guitar is being played to produce different chord combinations. More specifically the apparatus is applicable to a pedal steel guitar having a series of tone changers adjacent a bank of horizontal guitar strings for selectively tightening or loosening the tension on each string, and having a group of pedals or knee levers, or both, for selectively actuating the individual tone changers.

In pedal steel guitars of the type known to the art and disclosed in various US. patents such as Jackson US. Pat. No. 3,407,697, Kelley US. Pat. No. 3,390,600, Elmore U.S. Pat. No. 3,163,073, and Lashley patent No. 3,447,413, tone changing mechanisms of widely varying designs have been employed to aid the guitar player in effecting tone changes beyond those which can be produced by hand alone. Although the versatility and sophistication of such mechanisms has improved throughout the years, they still retain certain inherent disadvantages and limitations which have prevented the development of a steel guitar capable of producing a sufficiently wide variety of tone combinations and chord structures needed for certain types of musical compositions and arrangements.

These limitations are primarily the result of spacial restrictions in the guitar itself, which limit the number of pedals or levers which can be coupled with the tone changers and therefore limit the number of separate tone changing actions available to the player. Moreover the number of strings that can be controlled and the number of steps through which a string can be raised or lowered by a single tone changing action have been limited by the restricted space available for the tone changing linkages. In an effort to solve these problems, some designers have utilized compression links as well as tension links to actuate the individual tone changers. However such systems are much more difficult to tune and maintain in proper adjustment than are systems which utilize solely tension links.ln addition, the flexibility available in prior art designs for altering the pedal linkage to produce tone changing combinations other than those originally provided for by the manufacturer has been extremely limited, generally requiring time consuming disassembly of the guitar to make the linkage changes.

SUMMARY OF THE PRESENT INVENTION The present invention is directed to a guitar tone changing system of the general type described in which multifunction pedals, knee levers, or a combination of both are coupled through versatile, space-saving linkages with tone changers mounted at both ends of the guitar strings. Each guitar string has an individual tone changer at each of its ends, either tone changer being capable of selectively tightening or loosening the guitar string from its pre-set tension. Each tone changer is actuated by a pair of tension members, one of which causes the tone changer to tighten the string and the other of which causes the tone changer to loosen the string when pulled. The tension members are connected to one or more cranks protruding from a series of rotatable axles mounted transversely to the guitar strings. Each axle has two rows of sockets extending throughout its length, one row facing upwardly and the other facing downwardly. Each socket contains threads for engaging a mating threaded portion of an individual crank. Depending upon what tone changing combination is to be performed by a particular axle, a number of cranks corresponding to the number of tension members to be pulled are seated in respective sockets on the axle at locations suitable for engaging the respective tension members. Thereafter, whenever the axle is rotated, the attached tension members are pulled and the desired tone changing combination is accomplished. Some axles may be arranged to rotate in either of two directions, pulling some tension members when rotated in one direction and other tension members when rotated in the other direction.

Each axle is linked to a pedal or knee lever so that the axle is rotated when the corresponding pedal or knee lever is actuated. The pedals are so constructed that each is capable of performing more than one tone changing action, and multiple linkages from each pedal transmits these separate tone changing actions to the proper axle. Some of the pedals comprise a primary lever with a secondary lever mounted thereon which can be selectively actuated simultaneously with the primary lever if desired. These pedals are each capable of two separate tone changing actions. For example if the player actuates only the primary lever, a particular axle will rotate and cause a particular combination of tone changes. Alternatively, if the player actuates the secondary lever simultaneously with the primary lever, a second linkage either rotates the same axle through an additional angle, thereby raising or lowering by steps the tone combination produced by the first lever, or rotates a different axle which pulls on different tension members to produce a different tone combination. Other pedals are each capable of performing four separate tone changing actions by virtue of the fact that they have primary and secondary levers, and are universally mounted for rotation about either a horizontal or a vertical axis. These pedals include not only linkages from the two levers to the respective axles but also include a vertical torque transmission shaft having cranks protruding horizontally therefrom for connection to selected tension members.

The knee lever system comprises a group of six levers for each knee, each rotating a separate axle when actuated. Two of the levers are positioned horizontally for rotation about respective transverse axes, with their free ends sufficiently near to one another that each can be actuated separately or both can be actuated simultaneously, the latter action caused by pressing a knee between them. Near the outer journaled end of each horizontal lever is one of a second pair of levers of the set, each depending vertically from its respective transverse axle. These vertical levers can be actuated individually, or can be actuated simultaneously with their adjacent horizontal levers. A third pair of levers are positioned horizontally end-to-end at a location inboard of the other four levers and at a level slightly below that of the first pair of horizontal levers. Each of the third pair of levers rotates about a vertical axis, but is otherwise similar to the first pair of levers. The six levers are closed enough together that they can be actuated not only individually or in groups of two, but also simultaneously in groups of three if desired. These variations make it possible to selectively produce any of a great number of different tone changing actions with one knee. An identical set of levers is provided for the other knee.

The individual tone changers which selectively tighten or loosen the guitar strings each comprise a vertical three-arm linkage with the first, or string engaging, arm mounted for rotation about a horizontal axis. The second arm is pivotally connected to the bottom of the first arm and is engaged at different locations by two tension members One of the tension members, when pulled, causes the first arm to rotate in a direction so as to tighten the string. The other tension member causes the first arm to rotate in the opposite direction so as to loosen the sring. Both tension members have portions which extend beyond their points of engagement with the second arm and include adjustable stops for limiting the extent to which each member can be pulled. These extended portions each include adjustable fulcrums for engaging the second arm so as to permit it to rotate about one of the fulcrums when the opposite tension member is being pulled. The third arm of the linkage is pivotally connected to the bottom of the second arm and is coupled with a spring which restrains the linkage from allowing the guitar string to loosen. The portion of the first arm which actually engages the guitar string comprises a hardened steel insert to prevent excessive wear of the arm.

Means for guiding the guitar player in the conventional hand method of tone changing are also provided. A tone marking panel is detachably mounted by means of magnets to the sounding board beneath the guitar strings so that it can be easily removed and replaced with a panel having different colored or coded tone making guides.

A number of significant advantages result from the novel features utilized in the tone changing system of the present invention. The provision of double and quadruple function pedals, and a knee lever system permitting a great number of different possible actions with each knee, provide the guitar player with substantially more tone changing actions than have ever before been available on guitars of the type described. In order to make use of the exceedingly high number of possible tone changing actions available to the player, tone changers are provided at both ends of each string capable of either tightening or loosening the string from its initial pre-set tension. These provide a marked increase both in the number of strings that can be controlled and in the number of steps through which each string can be raised or lowered by a single tone changing action. Moreover the provision of such tone changers at both ends of each string makes it possible to utilize tension members exclusively to transmit all tone changing actions. Furthermore the provision of transverse rotatable axles at the heart of the linkage system, having upper and lower cranks rotatable in either of two directions, allows far more linkage combinations within the limited space available than were previously obtainable with prior art tone changing systems. In addition, the means for easily attaching or detaching the cranks, or changing their positions on the axles, greatly facilitates the alteration of the tone changing linkage system when desired and allows extreme flexibility in the programming of the guitar for desired tone changing combinations.

The foregoing and other objectives, features and advantages of the present invention will be more readily understood upon consideration of the following detailed description of the invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a rear perspective view of a pedal steel guitar embodying the tone changing apparatus of the present invention.

FIG. 2 is an enlarged, partially sectional side view showing the exposed primary elements of the tone changing apparatus of the present invention.

FIG. 3 is a side view of a double function pedal taken along line 3-3 of FIG. 2.

FIG. 4 is an enlarged, partially exploded fragmentary view of one of the rotatable transverse axles utilized in the present invention.

FIG. 5 is a partially sectional side view of a quadruple function pedal and its associated tone-changing linkage.

FIG. 6 is a fragmentary side view of an alternative type of tone changer for the keyhead of the guitar.

DESCRIPTION OF THE PREFERRED EMBODIMENT The pedal steel guitar, designated generally as 10 in FIG. 1, comprises a horizontally extending sounding board frame 12 supported at each end by a pair of legs 14. Two series of tone changers, 18 and 20 respectively, are mounted in transverse array on the frame 12, one series adjacent each end of the frame. Each separate tone changer 18 is longitudinally aligned with a tone changer 20, and between each such pair of tone changers is stretched one of a bank of parallel guitar strings 22. A tone marking panel 24 is mounted horizontally on top of the frame 12 beneath and parallel to the bank of guitar strings 22. The tone marking panel 24 contains tone marking guides 26 which are spaced more narrowly apart toward the head of the guitar (i.e., the end where tone changers 20 are located) and more widely spaced toward the opposite end of the guitar. Although only a single bank of guitar strings is shown in FIG. 1, multiple banks of strings, each with its associated tone changers and tone marking panel, could be used for greater versatility.

The guitar of FIG. 1 is arranged for a left handed guitar player who, while standing or sitting and facing the rear side 27 of the guitar, picks the strings 22 with his right hand while pressing a bar against the strings with his right hand according to the tone marking guides 26. The pressing of the bar on the strings 22 at various locations as indicated by the guides 26 changes the vibrating lengths of the various strings and thereby changes their respective tones. However the tone changing which can be brought about in this fashion is severely limited, and therefore each string 22 is stretched between a tone changer l8 and a tone changer 20 to produce tone changing combinations in addition to those produced by hand.

As illustrated in FIG. 2 with respect to tone changer 20, each tone changer includes a vertical arm 28 journaled by a bearing 29 for rotation about a horizontal shaft 30 which is secured to the frame 12. The rotation of each vertical arm 28 is controlled by a second arm 32 pivotally connected to arm 28 by a pin 34. Arm 32 in turn is controlled in a manner to be described hereafter by selective actuation of an upper tension member 36 and a lower tension member 38 respectively.

When neither of the tension members 36 and 38 is actuated, arm 28 assumes a rotational position which will be referred to as its normal position. When both tone changers 18 and 20 of string 22 have their respective arms 28, 28a in their normal positions, the string 22 can be tuned by adjusting it to its proper initial preset tension. This is accomplished by turning tension adjusting key which is mounted on arm 28 of tone changer 20. It will be noted that the opposite end of string 22 is secured to the corresponding arm 28a of tone changer 18 by means of a fixed pin 42.

Once string 22 has been adjusted to its proper pre-set tension, this tension can thereafter be increased or decreased by the rotation of one or both of the arms 28, 28a about their respective shafts 30. If arm 28 is rotated from its normal position clockwise to the position shown in FIG. 2, the effect is to loosen the tension on string 22. The string is further loosened if arm 28a is rotated from its normal position counterclockwise to the position shown in FIG. 2. Conversely arms 28 and 28a respectively can be rotated in the opposite directions from their normal positions, either singly or together, to cause tightening of string 22 from its pre-set tension.

It should be noted that the arms 28 and 28a each include curved top portions for engaging the respective ends of the string 22, and it is at these portions that wear is likely to occur between the string and the arm. Therefore hardened steel inserts are preferably provided at these points to prevent excessive wear.

The position and rotational movement of arms 28 and 28a are controlled in identical fashion by actuation of their respective second arms 32 and 32a. Arm 32 of tone changer 20, which is typical of all the tone changers utilized in the invention, is controlled by its engagement with three different members. Two of these are upper tension member 36 and lower tension member 38 respectively. Each of the two tension members includes a slotted member 44 and 46 respectively through which arm 32 passes. The slots are large enough so that arm 32 fits loosely within the slots, and thus arm 32 may assume various angles with respect to the slotted members 44 and 46. The tension members 36 and 38 also include threaded portions 48 and 50 respectively which extend beyond the slotted members. Each such portion includes a threaded adjustable stop 52 which limits the extent to whicheach of the tension members 36 and 38 can be pulled to the right in FIG. 2 by its abutment with frame 12. In addition, threaded portions 48 and 50 include threaded adjustable stops 54 which, by their engagement with the inner surface of frame 12, limit the extent to which tension members 36 and 38 can move to the left.

The third member acting on arm 32 is spring 56, the tension of which is adjustable by means of screw 58. Spring 56continually pulls arm 32 toward the left in FIG. 2, acting through a third arm 60 which is pivotally connected to the lower end of arm 32 and slidably mounted in a guide 61. The utilization ofa third arm 60 to connect spring 56 to arm 32, rather than a direct connection, makes it possible to use a longer spring without extending the length of frame 12.

When neither tension member 36 nor 38 is being pulled to the right, arm 28 assumes its normal position. Such position is established by the extent to which stops 54 allow tension members 36 and 38 to be pulled to the left by the combined force of spring 56 acting on the lower end of arm 32 through arm 60, and the force exerted by the tension of string 22 acting on the top of arm 32 through arm 28. Under the influence of these two forces, stops 54 of members 36 and 38 are both forced into abutment with the inner surface of frame 12.

When string 22 is to be loosened from its initial preset tension, lower tension member 38 is pulled to the right. Arm 32 pivots in a counterclockwise direction about its point of abutment with upper slotted portion 44 allowing arm 28 to pivot in a clockwise direction and loosening the tension on string 22. The degree of pivoting, and thus the degree to which the tension is decreased is controlled by adjustable stop 52 of tension member 38 which limits the extent to which tension member 38 can be pulled to the right.

If the tension on string 22 is to be increased from its initial pre-set value, tension member 36 is pulled rather than tension member 38. This causes arm 32 to rotate in a clockwise direction about its point of abutment with lower slotted portion 46, causing arm 28 to rotate in a counterclockwise direction and increasing the tension on string 22. The degree to which the tension is increased is similarly limited by the adjustment on stop 52 of tension member 36.

It should be noted that spring 56 always applies force on the tone changer 20 in a manner so as to restrain the tone changer from allowing string 22 to be loosened, and thereby keeps arm 28 in its normal position unless tension member 36 or 38 is pulled. When either tension member 36 or 38 is pulled, the slotted member of the tension member opposite the one being pulled acts as a fulcrum about which arm 32 rotates, and the position of the fulcrum is determined by the adjustment of the corresponding stop 54.

FIG. 6 illustrates an alternative type of tone changer 200 which may be used in conjunction with a keyhead of more conventional design wherein the keys are arranged in a pair of substantially longitudinal rows with respect to the guitar strings, rather than in a single transverse row as shown in FIGS. 1 and 2. Each tone changer 200 comprises a vertical arm 228 rotatably mounted on a respective string winder 230 and controlled by a second arm 232 in the same manner as was previously described for controlling the vertical arm 28 of each tone changer 20. The top of the arm 228 includes a finger portion 234 which projects sideways and engages a respective guitar string 236 from underneath. By rotating the arm 228 in a counterclockwise direction, the finger 234 will push upwardly against the string, thereby increasing its tension and raising its tone. Alternatively, if the arm 228 is rotated in a clockwise direction, the string will be loosened from its preset tension. Stop screws 238 and 240 respectively may be used for fine adjustment on the limits through which the arm 228 may rotate.

As will be apparent to those skilled in the art, other alternative structures for the tone changer 200 are possible. For example, each separate tuning key mechanism 242 could be rotatably mounted to the keyhead housing 244 rather than fixed to it as shown in FIG. 6. In such case arm 228 would be attached directly to the tuning key mechanism 242 and, rather than regulate the tension of the string by means of a finger 234,

would instead regulate the tension by controlling the relative rotational position of the tuning key mechanism 242 and its attached string winder 230. Such structure would achieve the desired tone changing result if the diameter of the string winder 230 were sized proportionately to the degree of rotation of the arm 228.

In addition, the structure of FIG. 6 might be further altered by placing the finger 234 above, rather than below, the string 236, thereby exerting pressure in theopposite direction. The effect of such structure would be to reverse the action of the tone changer 200, with the upper tension member connected to arm 232 lowering rather than raising the tone of the string when pulled, and the lower tension member performing the opposite function. In such case the spring (corresponding to spring 56 in FIG. 2) would have to be located so as to exert tension in the opposite rotational direction from that shown in FIG. 2. A reversed tone changing action of the type just described could also be achieved with the alternative structure mentioned in the previous paragraph, wherein the arm 228 is connected directly to the tuning key mechanism 242. Reversal could be accomplished simply by reversing the direction in which the string 236 is wound on the string winder 230. This reversal of tone changing action at the keyhead may be helpful to facilitate the programming of the guitar tone changing mechanism, for reasons to be described hereafter.

Tension members 36 and 38 of tone changer 20, and 36a and 38a of tone changer 18, together with the corresponding tension members of each of the other tone changers on the guitar, are coupled with centrally located actuator apparatus for selectively pulling the respective tension members to produce the appropriate tightening or loosening of each string for the desired tone changing combinations. The actuator apparatus comprises a series of rotatable axles 62 mounted within the sounding board frame 12 transversely to the bank of guitar strings 22. As best illustrated in FIG. 4, the ends of each axle 62 are journaled for rotation in appropriate bearings or bushings 64 located at spaced intervals along the longitudinal side panels of frame 12. For ease in assembly and disassembly, the side panels have an upper portion 66 and a lower portion 68 detachably fastened to the upper portion 66 by means of vertical screws (not shown). By removing the screws and lower portion 68, the axles 62 can be easily mounted or removed.

The number of rotatable axles 62 mounted within frame 12 depends on the number of actuating pedals and levers, and the space available between the two sets of tone changers l8 and respectively for the axles and their related linkage. Although in FIG. 4 the bearing mounts 64 for the axles 62 are illustrated as being on the same level, it might be desirable in certain instances to mount some axles at different levels from others in order to achieve maximum space utilization.

The axles 62 each have a series of sockets 70 spaced longitudinally along the axle. The number and position of the sockets depend on the number and transverse spacing of the tone changers 18, 20. The objective is to provide as many available sockets as possible for the mounting of actuator cranks to pull the tension member of the tone changers. The sockets 70 are preferably drilled completely through the diameter of axle 62 and are threaded to accept the insertion of upper and lower actuator cranks 72 and 73 respectively, which contain mating threaded male portions 74.

Axle 62 is mounted within frame 12 so that in its normal position sockets 70 are vertically oriented. The

number and positions of upper cranks 72 and lower cranks 73 mounted on any particular axle 62 depend entirely on the tone changing function which is to be transmitted by the rotation of the axle to the tone changers 18, 20. If only one tone changer is to be actuated, then only one crank need be provided on the axle. Its transverse position on the axle will be a convenient one for connection to the appropriate tension member of the tone changer, and whether an upper or lower crank is utilized will depend on the position of the tension member and the direction of rotation of the axle. For actuation of a plurality of tone changers, a like number of actuator cranks will be provided.

As an example, the operation of an axle 62a illustrated in FIG. 2 will be described. Axle 62a is coupled with a pedal 76 in such a way that depression of the pedal rotates the axle 62a in a clockwise direction from its normal unactuated position where its sockets are vertical. If the tone of the particular string 22 shown in FIG. 2 is to be changed by the clockwise rotation of axle 62a from its normal position, then at least one crank 72 or 73 must be inserted in a socket 70 of the axle corresponding to the transverse position of the particular string 22 and its associated tone changers 18 and 20. If the clockwise rotation of axle 62a is intended to loosen string 22 from its initial pre-set tension, but only by half a step, a lower crank 73 is provided in the appropriate socket 70 and a tension rod 78 passes loosely through an aperture 80 in a swivel member 81 rotatably mounted on the crank 73 (See FIG. 4) and attaches by a hook or other conventional means to one of the eyes 82 of tension member 38a. A collar 84 is affixed by a set screw to the tension rod 78 in such a position that the tension rod 78 is pulled to the left by the clockwise rotation of axle 62a. For smooth operation a spring 86 is preferably placed between the collar 84 and the swivel member 81. The pulling of the tension rod 78 to the left by the rotation of axle 62a causes tension member 38a also to be pulled to the left, which in turn causes tone changer 18 to loosen string 22 from its pre-set tension in the manner previously described.

If the clockwise rotation of the axle 62a is intended to loosen string 22 from its initial pre-set tension by a full step rather than a half step as in the previous example, an upper crank 72, appropriately positioned, is provided in addition to lower crank 73 and is attached to lower tension member 38 of tone changer 20 by a tension rod 88. Such construction however requires that tension rod 88 slant downwardly from crank 72 to tension member 38, and since the presence of other axles may interfere with the passage of such a slanted rod under some circumstances it may be desirable instead to use a conventional cable and pulley arranged in any convenient manner between crank 72 and tension member 38 to avoid interference with the other linkage.

A similar construction could be used to connect lower cranks such as 73 with upper tension members where necessary. The latter instance could occur if it were intended that clockwise rotation of crank 62a should tighten string 22 from its initial pre-set tension rather than loosen it. In such case upper crank 72 would be attached to tension member 36 of tone changer 20, and if a full step rather than a half step rise were desired, crank 73 would be attached to tension member 36a of tone changer 18 in addition.

From the preceding discussion it will be recognized by those skilled in the art that reversing the action of the keyhead tone changers in the manner previously described, so that the upper tension member 36 loosens the guitar string and the lower tension member 38 tightens it, while leaving the tone changers at the opposite end of the guitar in the same configuration as illustrated in FIG. 2, will avoid the need for the slanted rod or cable-and-pulley arrangement just described when it is desired to loosen or tighten the particular guitar string from its initial pre-set tension by a full step rather than a half step.

If the tones of more than one string are to be changed by the actuation of axle 62a, the axle is equipped with additional cranks at other transverse locations and associated linkage connecting these cranks to the appropriate tension members of the various tone changers. Since in practice there are a number number of axles 62 spaced longitudinally along the guitar, it will be desirable to use horizontal tension rods wherever possible to actuate the tone changers, since one such rod may traverse a number of axles 62, and any one of such axles may actuate the horizontal tension rod if the axle is equipped with a crank for engaging the rod.

Actuation ofa specific axle 62 is accomplished by actuating the particular pedal or lever connected to the axle for producing the particular tone changing effect for which the axle has been programmed. A large number of the axles 62 are each actuated by one ofa series of double-function pedals 76. Each of these pedals comprises a primary foot actuated lever 90 journaled for rotation about a horizontal rod 92 which extends longitudinally along the rear of the guitar between a pair of legs 14. Each lever 90 is connected to a respective axle by a link 94, best illustrated in FIG. 2 with respect to axle 62a. The link 94 is coupled to the lever 90 by means of a pin 95, and extends upwardly from the pin through an actuating crank 96 protruding perpendicularly from the axle and beyond the crank through a stop plate 98 which is fastened to the side panel of frame 12. Upon the downward application of foot pressury against the foot engaging surface 91 of lever 90, the link 94 pulls down on crank 96 through the engagementof adjustable nut 100 with the crank. This rotates the axle 62a in a clockwise direction from its normal position. The angle through which the axle is rotated by the depression of lever 90 is limited by the abutment of an adjustable stop 102 with stop plate 98. Tone changer spring pressure, or string tension as the case may he, returns the axle to its normal position when the pedal is released.

A secondary foot actuated lever 104 is rotatably mounted by pin 95 to lever 90 so that it too may rotate about a horizontal axis. The lever 104 includes a toe engaging piece 106 located adjacent the foot engaging surface 91 of the primary lever 90. The location of the toe engaging piece 106 enables the guitar player, if he wishes, to actuate the secondary lever I04 simultaneously with his depression of the primary lever 90. He accomplishes this simply by pushing his foot forward on the surface 91 and applying pressure to the toe engaging piece 106, thereby rotating lever 104 in a clockwise direction as viewed in FIG. 3. An upwardly exposed roller 108 facilitates this forward foot movement.

A link 110 extends upwardly from lever 104 through actuating crank 96 and stop plate 98 in a manner similar to link 94. The only difference is that the adjustable stop 112 of link 110 is initially adjusted at a higher elevation than stop 102 of link 94. This enables link 110 to be pulled downwardly to a greater extent than link 94 by the rotation of secondary lever 104. The result is that axle 62a is rotated through an angle of rotation in addition to that allowed by adjustable stop 102 upon the actuation of lever 104. Stop 1 12 would normally be adjusted so as to allow an additional angle of rotation sufficient to cause a half or whole step change in the chord combination produced by the actuation of lever alone.

Alternatively, it might be desirable under certain circumstances to couple link with a rotatable axle other than the one to which link 94 is attached. For example, link 110 might be connected with an actuating crank of a neighboring axle so that upon actuation of lever 104 while lever 90 is depressed additional tone changers are actuated by the neighboring axle simultaneously with the actuation of those tone changers linked with axle 62a. The result would be a differently structured chord combination.

Links 94 and 110 respectively each have a hook and eye arrangement 116 whose primary function is to allow easy detachment of the bank of pedals 76 from the rotatable axles 62 without disturbing the adjustment of the various nuts and stops associated with the axles. Such disassembly is necessary when the legs 14 are removed from the frame 12 for transportation of the guitar from one location to another.

Because there may be ten or more pedals 76 on a single guitar, it is preferable to coat the foot engaging surface 91 of each pedal with a different colored paint to help identify them. Since such guitars are commonly played under ultraviolet lighting conditions, fluorescent coatings are most desirable.

An alternative arrangement to that shown in FIG. 1 for the double function pedals 76 is an arrangement wherein every other pedal is made shorter, and mounted at a somewhat higher elevation, than its neighboring pedals on either side. It is believed that such arrangement will facilitate quick changes from one pedal to the other, and the simultaneous depression of multiple pedals when desired.

In addition to the double-function pedals 76, a pair of quadruple-function pedals 118 may also be provided on the guitar, preferably mounted at the head of the guitar on a rod 120 supported between two legs 14. As best illustrated in FIG. 5, each quadruple-function pedal 118 comprises a primary lever 122 and a secondary lever 124. The primary lever 122 is universally mounted by a ball joint 126 for rotation about both a horizontal and a vertical axis. The secondary lever 124 is mounted on the end of lever 122 by a pin 128.

When foot pressure is applied to the top of the primary lever 122 the lever rotates downwardly about the ball joint 126 and pulls down on link 130, which rotates axle 62c clockwise similarly to the manner in which axle 62a is actuated. If, while lever 122 is depressed, the player wishes to make an additional tone change, he moves his foot to the right in FIG. 5 and rotates secondary lever 124 in a clockwise direction about pin 128. Lever 124 is coupled by means of link 132 with a bell crank 134 pivotally mounted on the top of lever 122. Link 132 pivots bell crank 134 is a clockwise direction which pulls link 136 down to perform a function similar to that performed by link 110 with respect to axle 6241.

In addition to links 130 and 136, pedal 118 is also linked to the tone changing system of the guitar through a torque transmission shaft 138. The shaft is fixed at its lower end to the primary lever 122, and can be rotated in either direction by rotating primary lever 122 in a horizontal plane about ball joint 126. The top of the shaft 138 is rotatably journaled in a bracket 140, and a pair of arms 142, 143 extend horizontally from the shaft in opposite directions transverse to the strings of the guitar. Each arm 142, 143 is equipped with numerous transversely spaced apertures 144 so that one or more tension rods 146 and 148 can be connected between the arms 142, 143 and certain designated tone changers. When Iever' 122 is rotated sideways in one direction by foot pressure, arm 142 pulls on its tension rods 146 to change the tone of designated strings. When lever 122 is rotated in the opposite direction, arm 143 pulls on its tension rods 148, causing a different tone change.

It is possible that the guitar player may wish to transmit tone changes through shaft 138 and links 130 and 136 simultaneously. This is possible, since lever 122 can be depressed and rotated from side to side simultaneously. A universal joint 150 and an extension 152 at the top of the shaft 138 make it possible for the lever 122 to be depressed by allowing the shaft 138 to bend at the universal joint and allowing the top of the shaft to be pulled downwardly without encountering resistance from the bracket 140. Furthermore, ball joint connections 158 are provided at the base of links 130 and 136 so that horizontal rotation of the lever 122 will not interfere with the operation of the links.

In addition to the double-function pedals 76 and the quadruple-function pedals 118, two sets of six knee levers, each lever fixed to a separate axle, may be provided. Each set of levers includes two normally horizontal levers 154 and 156 (FIG. 1) arranged end to end, with their outer ends fixed to respective transverse axles and their inner free ends sufficiently near to one another that each can be actuated separately or both can be actuated simultaneously. Actuation is by upward knee pressure, and simultaneous actuation is accomplished by pressing the knee upwardly between the levers.

Near the outer end of each of the levers 154 and 156 one of the other two levers of the set, 160 and 162, hangs vertically from a respective transverse axle. Each of the levers 160, 162 is actuated by pressing the knee sideways against the inner surface of the lever and rotating it outwardly from the other levers. Each vertical lever is close enough to its neighboring horizontal lever that the two can be actuated simultaneously if desired by pressing the knee against both of them. In addition, the two horizontal levers 154 and 156 are sufficiently close to each other and to each of the two vertical levers 160 and 162 that it is possible to actuate the two horizontal levers simultaneously with either one of the vertical levers by pressing the leg against all three.

A third pair of levers 168 and 170 respectively are positioned horizontally end-to-end at a location inboard (in a direction away from the guitar player) of the other four levers, and at a level slightly below that of the first pair of horizontal levers. The outer end of each of the third pair of levers is mounted on a rotatable vertical torque transmission shaft similar in construction to the top portion of torque transmission shaft 138, enabling each such lever to rotate about a vertical axis. Thus each lever 168 and can be actuated independently by inward pressure of the knee, or both may be actuated simultaneously by inward knee pressure between them. In addition, each of the levers 168 and 170 can be actuated simultaneously with one or more of the other horizontal or vertical levers in the group if desired, thereby making it possible for the guitar player to selectively produce any of a great number of different tone changing combinations with one knee. An identical set of levers is provided for the other knee.

An additional feature of the guitar which adds to its versatility is the provision of means for easily removing and replacing the tone marking panel 24. The tone marking panel is mounted to the top of the sounding board frame 12 and lies horizontally beneath the guitar strings 22. Under certain circumstances it is desirable to change the coloring or other arrangement of the tone marking panel to enable the musician to adapt to different playing situations. To facilitate such removal and replacement, the tone marking panel is provided with a pair of longitudinal metal strips 164 (FIG. 2) fastened to the underside of the panel adjacent its outer longitudinal edges. The frame 12 is provided with a series of longitudinally spaced magnets 166 positioned to correspond with the locations of the metal strips 164 so that the attraction between the magnets 166 and the metal strips 164 holds the tone marking panel 24 in place. When it is necessary to replace the tone marking panel, it is simply lifted by force from the magnets and another panel is positioned in its place.

The terms and expressions which have been employed in the foregoing abstract and specification are used therein as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.

I claim:

1. Apparatus for selectively tightening and loosening the strings of a guitar while the guitar is being played to change the tone of the strings and thereby produce different chord combinations comprising:

a. a first tone changer mounted adjacent one end of a particular string for either increasing or decreasing the tension on said string from an initial pre-set tension;

b. a second tone changer located adjacent the opposite end of said same string for either increasing or decreasing the tension on said string from said initial pre-set tension;

c. a first pair of tension members attached to said first tone changer at different locations for causing said first tone changer to tighten said string when one of said members is pulled and loosen said string when said other member is pulled;

d. a second pair of tension members attached to said second tone changer at different locations forcausing said second tone changer to tighten said string when one of said members is pulled and loosen said string when said other member is pulled; and loosen said string when said other member is pulled; and

e. actuator means for selectively pulling one or more of said tension members at any one time so as to loosen said string at both ends, or tighten said string at both ends, said actuator means comprising a rotatable axle mounted transversely to said string having at least two cranks affixed thereto, one of said cranks being attached to one of said first pair of tension members and the other of said cranks being attached to the identically functioning one of said second pair of tension members for pulling said attached tension members simultaneously when said axle is rotated and thereby either tightening or loosening said string simultaneously at both of its ends.

2. The apparatus of claim 1 including a tone marking apparatus for said guitar to aid the player in tuning the guitar and manually changing the tone of the individual guitar strings comprising a horizontally extending sounding board, a bank of parallel guitar strings extending horizontally above said sounding board, a tone marking panel mounted on said sounding board beneath and parallel to said bank of strings and means for detachably coupling said tone marking panel to said sounding board.

3. The apparatus of claim 1 wherein a set of said first and second tone changers are provided for each of several of said guitar strings, and wherein said actuator means includes-a pedal comprising a first foot actuated lever and first coupling means connecting said first lever with a' group of said tone changers for simultaneously adjusting the tension on each of a selected group of guitar strings; and a second foot actuated lever mounted on said first lever for selective actuation simultaneously therewith, said second lever having second coupling means connecting it with a group of said tone changers for causing string tension adjustments other than the tension adjustments caused by actuation of said first foot lever alone.

4. The apparatus of claim 3 wherein said first and second coupling means include means for connecting said first and second levers respectively with the same group of said tone changers, and wherein said second lever and said second coupling means include means for loosening or tightening the strings engaged by said group of tone changers to a greater degree than is caused by actuation of said first lever alone.

5. The apparatus of claim 3 wherein said first and second coupling means include means for connecting said first and second levers respectively with different groups of said tone changers.

6. The apparatus of claim 3 wherein said first lever includes mounting means for permitting said first lever to rotate downwardly about a horizontal axis and further includes an upwardly facing foot engaging surface offset from said mounting means for depressing said first lever when foot pressure is applied thereto, and wherein said second lever is journaled to said first lever for rotation about a horizontal axis and includes a toe engaging piece located between said foot engaging surface and said mounting means for actuating said second lever when said foot is moved toward said mounting means.

7. The apparatus of claim 3 wherein said first lever includes mounting means for permitting said first lever to rotate about both a horizontal axis and a substantially vertical axis and further includes a substantially vertical torque transmission shaft coupling said first lever with one or more of said tone changers for adjusting string tension when said first lever is rotated about said vertical axis.

8. Apparatus for selectively adjusting guitar string tension while the guitar is being played to change the tone of the strings and thereby produce different chord combinations comprising:

a. tone changing means comprising a series of tone changers adjacent a horizontal bank of I guitar strings, each engaging a respective guitar string, for selectively adjusting the tension on said guitar strings; and

b. a pair of knee levers coupled with said tone changing means for adjusting the tension on said guitar strings, each said knee lever being mounted for rotation about one of two separate horizontal axes transverse to and spaced longitudinally along said bank of guitar strings and each said lever having a free end extending in its normal unactuated position substantially horizontally from its respective axis of rotation toward the free end of said other lever, the adjacent free ends of said pair of knee levers being sufficiently close together to enable them to be engaged and rotated upwardly simultaneously by a knee pressed upwardly at the midpoint between them.

9. The apparatus of claim 8 including a second pair of knee levers coupled with said tone changing means and mounted longitudinally on either side of said first pair of levers, each mounted for rotation about a horizontal axis transverse to said bank of guitar strings and each having a free end normally suspended in a substantially vertical position from its respective axis of rotation to a point below said first pair of levers.

10. The apparatus of claim 8 including another pair of knee levers coupled with said tone changing means, each mounted for rotation about a separate vertical axis spaced transversely inboard of said first pair of knee levers and each said lever having a free end extending in its normal unactuated position substantially parallelto said first pair of leverstoward the free end of said other inboard lever. 

1. Apparatus for selectively tightening and loosening the strings of a guitar while the guitar is being played to change the tone of the strings and thereby produce different chord combinations comprising: a. a first tone changer mounted adjacent one end of a particular string for either increasing or decreasing the tension on said string from an initial pre-set tension; b. a second tone changer located adjacent the opposite end of said same string for either increasing or dEcreasing the tension on said string from said initial pre-set tension; c. a first pair of tension members attached to said first tone changer at different locations for causing said first tone changer to tighten said string when one of said members is pulled and loosen said string when said other member is pulled; d. a second pair of tension members attached to said second tone changer at different locations for causing said second tone changer to tighten said string when one of said members is pulled and loosen said string when said other member is pulled; and loosen said string when said other member is pulled; and e. actuator means for selectively pulling one or more of said tension members at any one time so as to loosen said string at both ends, or tighten said string at both ends, said actuator means comprising a rotatable axle mounted transversely to said string having at least two cranks affixed thereto, one of said cranks being attached to one of said first pair of tension members and the other of said cranks being attached to the identically functioning one of said second pair of tension members for pulling said attached tension members simultaneously when said axle is rotated and thereby either tightening or loosening said string simultaneously at both of its ends.
 2. The apparatus of claim 1 including a tone marking apparatus for said guitar to aid the player in tuning the guitar and manually changing the tone of the individual guitar strings comprising a horizontally extending sounding board, a bank of parallel guitar strings extending horizontally above said sounding board, a tone marking panel mounted on said sounding board beneath and parallel to said bank of strings and means for detachably coupling said tone marking panel to said sounding board.
 3. The apparatus of claim 1 wherein a set of said first and second tone changers are provided for each of several of said guitar strings, and wherein said actuator means includes a pedal comprising a first foot actuated lever and first coupling means connecting said first lever with a group of said tone changers for simultaneously adjusting the tension on each of a selected group of guitar strings; and a second foot actuated lever mounted on said first lever for selective actuation simultaneously therewith, said second lever having second coupling means connecting it with a group of said tone changers for causing string tension adjustments other than the tension adjustments caused by actuation of said first foot lever alone.
 4. The apparatus of claim 3 wherein said first and second coupling means include means for connecting said first and second levers respectively with the same group of said tone changers, and wherein said second lever and said second coupling means include means for loosening or tightening the strings engaged by said group of tone changers to a greater degree than is caused by actuation of said first lever alone.
 5. The apparatus of claim 3 wherein said first and second coupling means include means for connecting said first and second levers respectively with different groups of said tone changers.
 6. The apparatus of claim 3 wherein said first lever includes mounting means for permitting said first lever to rotate downwardly about a horizontal axis and further includes an upwardly facing foot engaging surface offset from said mounting means for depressing said first lever when foot pressure is applied thereto, and wherein said second lever is journaled to said first lever for rotation about a horizontal axis and includes a toe engaging piece located between said foot engaging surface and said mounting means for actuating said second lever when said foot is moved toward said mounting means.
 7. The apparatus of claim 3 wherein said first lever includes mounting means for permitting said first lever to rotate about both a horizontal axis and a substantially vertical axis and further includes a substantially vertical torque transmission shaft coupling said first levEr with one or more of said tone changers for adjusting string tension when said first lever is rotated about said vertical axis.
 8. Apparatus for selectively adjusting guitar string tension while the guitar is being played to change the tone of the strings and thereby produce different chord combinations comprising: a. tone changing means comprising a series of tone changers adjacent a horizontal bank of guitar strings, each engaging a respective guitar string, for selectively adjusting the tension on said guitar strings; and b. a pair of knee levers coupled with said tone changing means for adjusting the tension on said guitar strings, each said knee lever being mounted for rotation about one of two separate horizontal axes transverse to and spaced longitudinally along said bank of guitar strings and each said lever having a free end extending in its normal unactuated position substantially horizontally from its respective axis of rotation toward the free end of said other lever, the adjacent free ends of said pair of knee levers being sufficiently close together to enable them to be engaged and rotated upwardly simultaneously by a knee pressed upwardly at the midpoint between them.
 9. The apparatus of claim 8 including a second pair of knee levers coupled with said tone changing means and mounted longitudinally on either side of said first pair of levers, each mounted for rotation about a horizontal axis transverse to said bank of guitar strings and each having a free end normally suspended in a substantially vertical position from its respective axis of rotation to a point below said first pair of levers.
 10. The apparatus of claim 8 including another pair of knee levers coupled with said tone changing means, each mounted for rotation about a separate vertical axis spaced transversely inboard of said first pair of knee levers and each said lever having a free end extending in its normal unactuated position substantially parallel to said first pair of levers toward the free end of said other inboard lever. 